1. Field of the Invention
This invention relates generally to thermal inkjet printing. More particularly, this invention relates to an inkjet printer having an inkjet print cartridge that is substantially filled with printing fluid (i.e., with ink, for example), to such a print cartridge, and to a method for manufacturing such an inkjet print cartridge.
2. Related Technology
Inkjet printers or plotters typically have a print cartridge mounted on a carriage. This carriage is traversed back and forth across the width of a print medium (i.e., usually paper or a plastic plotting film, for example) as the print medium is fed through the printer or plotter. Plural orifices on the print cartridge are fed ink (or other printing fluid) by one or more channels communicating from a reservoir of the print cartridge. Energy applied individually to addressable resistors (or other energy-dissipating elements, for example, to piezoelectric actuators), transfers energy to printing fluid which is within or associated with selected ones of the plural orifices. This energy causes a portion of the printing fluid to momentarily convert to vapor phase and to form a vapor bubble. Thus, this type of printer is also sometimes referred to as a xe2x80x9cbubble jet printer.xe2x80x9d As a result of the formation and expansion of the vapor bubble, some of the ink is ejected out of the respective orifice toward the print medium (i.e., forming an xe2x80x9cink jetxe2x80x9d). As the ink is ejected, the bubble collapses almost simultaneously, allowing more ink from the reservoir to fill the channel. This quick ejection of an ink jet from a selected orifice, and almost simultaneous collapse of the bubble which caused this ejection, allows for the ink jet printing cycle to have a high repetition rate.
Customer demands and competitive pressures combine to create a desire for print cartridges to last as long as is practicable in such an ink jet printer. However, conventional ink jet print cartridges are not completely filled with printing fluid or ink even when they are brand new and freshly manufactured. This is the case because the exigencies and market economics of serial manufacturing for such ink jet print cartridges requires that they be filled with ink or printing fluid quickly using automated machinery. This automated machinery injects the ink into the print cartridges, and none of the injected ink dare spurt or leak out of the print cartridges during this filling process because it would interfere with subsequent manufacturing steps, and also could contaminate the automated ink filling machines. Thus, a volume cushion or lost volume of the print cartridge must be conventionally allowed, which lost volume is not filled with ink in order to be sure that none of the ink is leaked or spurted out of the cartridges during the ink filling step of serial manufacturing.
Consequently, for conventional ink jet print cartridges, there is a certain form factor characteristic of the exterior dimensions and volume of the cartridge, and of the concomitant internal volume of the ink reservoir defined within the print cartridge. Conventional ink jet print cartridges achieve only a fractional filling with ink of this form factor volume for the print cartridges, and do not achieve substantial filling with printing fluid of the printing fluid chambers of the conventional print cartridges. Consequently, conventional inkjet print cartridges have a shorter life, and provide a smaller number of characters printed or images formed than would be the case if the form factor for the cartridge were more fully utilized to contain printing fluid within the print cartridge.
Conventional ink jet print cartridges or components for such cartridges are seen in U.S. Pat. Nos. 3,930,260; 4,578,687; 4,677,447; 4,943,816; 5,560,837, and 5,706,039. However, none of these conventional ink jet print cartridges are believed to offer a substantial filling of the form factor volume of the print cartridge with printing fluid. Thus, all the known inkjet print cartridges require their replacement at more frequent service intervals than are desired. This frequency of replacement interferes, of course, with the use of the printers having such conventional inkjet print cartridges.
In view of the deficiencies of the related technology, an object for this invention is to reduce or overcome one or more of these deficiencies.
Accordingly, the present invention provides an inkjet print cartridge for ejecting printing fluid, the inkjet print cartridge comprising: a print cartridge body defining a chamber for receiving printing fluid, the print cartridge body carrying a printhead for controllably ejecting fine-dimension droplets of the printing fluid; the print cartridge body including a filling passage extending between but short of communication of the printing fluid chamber outwardly on the print cartridge body, and a penetrable diaphragm portion spanning and closing the filling passage.
According to another aspect, this invention provides a fluid jet printer having extended service intervals between changing of a print cartridge of the printer, the printer comprising: a base carrying a housing defining a printing path, a print medium feed mechanism controllably moving print medium through the printer along the printing path, a traverse mechanism carrying a fluid jet print cartridge for movement generally transversely to the printing path; the fluid jet print cartridge including: a cartridge body defining a printing fluid chamber, and carrying a printhead for controllably ejecting fine-dimension droplets of the printing fluid; the cartridge body including a filling passage extending between but short of communication of the printing fluid chamber outwardly on the print cartridge body, and an integral penetrable diaphragm portion spanning and closing the filling passage.
Still another aspect of the present invention provides a method of making a fluid jet print cartridge, the method comprising steps of: providing a print cartridge body defining a printing fluid chamber; providing a wall portion bounding the printing fluid chamber, and providing in the wall portion a filling passage extending between the printing fluid chamber and ambient but stopping short of communication of the printing fluid chamber outwardly of the print cartridge with ambient; providing a fine-dimension diaphragm portion at the filling passage, the fine-dimension diaphragm portion spanning and closing the passage and also bounding the printing fluid chamber; penetrating the fine-dimension diaphragm portion and injecting printing fluid into the printing fluid chamber; while injecting the printing fluid into the printing fluid chamber simultaneously utilizing the penetrated diaphragm portion to inhibit upwelling of printing fluid at the penetrated diaphragm portion and outwardly of the print cartridge along the filling passage.
Other objects, features, and advantages of the present invention will be apparent to those skilled in the pertinent arts from a consideration of the following detailed description of a single preferred exemplary embodiment of the invention, when taken in conjunction with the appended drawing figures, which will first be described briefly.